One new H7N9 avian flu case reported in China

For the third week in a row, China reported just one H7N9 avian influenza case, a sign that the fifth and biggest wave of infections may be drawing to a close.

In a regular update, Hong Kong's Center for Health Protection (CHP) said one case was reported from the mainland between Jul 14 and Jul 20, that of a 62-year-old woman from Jiangsu province who had exposure to a live poultry market. Her symptoms began on Jul 12.

The new illness raises the number of H7N9 cases in the fifth wave, which began last October, to 751. At least 282 deaths have been reported this season.Jul 21 CHP report

Earlier this week, the World Health Organization (WHO) provided more details about 21 H7N9 cases that China reported during the last half of June, noting two small clusters among the group. One involved two men, ages 79 and 48, who had been exposed to the same live poultry market in the city of Panzhihua in Sichuan province. The younger man, sickened first, was a poultry market seller and the older man, who died from his illness, lived above the market and passed through it regularly.

The other involves two women from the city of Wenshan in Yunnan province. One is a 33-year-old woman who started having symptoms on Jun 17 and was hospitalized the same day with severe pneumonia. She had no known exposure to live poultry. The other patient is her 42-year-old sister-in-law who became ill on Jun 21 after visiting the other woman. An investigation into the source of her illness found that she ran a shop near a poultry market and regularly bought live poultry there and that the source of her infection was probably the poultry market.

The WHO said since H7N9 was first detected in China in early 2013 it has received reports of 1,554 cases.Jul 19 WHO update

More Zika-related birth defects reported in the US, territories

In an update yesterday, the US Centers for Disease Control and Prevention (CDC) reported that three more babies have been born in the United States with Zika-related birth defects, pushing the total to 91. The number of pregnancy losses related to the virus remained at eight.

In the US territories, five more infants have been born with Zika-linked birth defects, raising the total to 127, and 1 more pregnancy loss was noted, putting that number at 8.

The totals are from two Zika pregnancy registries that the CDC maintains, one for the United States and the other for the US territories. Monitoring shows that 1,751 US women have completed their pregnancies with or without related birth defects, with the number at 2,945 for the US territories.Jul 20 CDC update

A large study that compared the performance of high- and standard-dose flu vaccine for preventing hospitalization of nursing home patients found an advantage for the higher-dose version, researchers based at Brown University reported yesterday in The Lancet Respiratory Medicine.

The randomized clinical trial was based on Medicare claims data and compared hospitalization rates in more than 38,000 residents of 823 nursing homes in 38 states during the 2013-2014 flu season in which the 2009 H1N1 virus was predominant. That strain usually has as a smaller impact on older adults when compared to H3N2.

About half (409) of the homes gave residents the high-dose vaccine while the other 414 provided the standard-dose version.

Hospitalization for respiratory illnesses was slightly but significantly lower in the high-dose group, 3.4% compared with 3.8% in the standard-dose group. Analysis of the relative risk of respiratory illness hospitalization found that the level was 12.7% lower for the high-dose group.

When the team looked at rates of hospitalization for any reason, they also saw significantly lower levels in the high-dose group. However, researchers did not find a significant difference in the rate of death between the two groups.

In a commentary on the study in the same issue, two influenza experts from the US Centers for Disease Control and Prevention wrote that the reduction in the in respiratory illness hospitalizations in the high-dose group is striking, and the 8.5% drop in all-cause hospitalization in the group was even more notable.

Though they said the evidence of better performance of the high-dose vaccine is strong, they urged cautious interpretation of the findings. The drop in all-cause hospitalization isn't surprising for two reasons, the authors noted. Hospitalizations coded as respiratory represented only one in five all-cause events, and typically only 10% of seasonal deaths from any reason in the elderly are from flu, even during seasons when there's a poor match between the vaccine and the circulating strain.